Monopropellant, as the name implies, is a single propellant ingredient which provides specific impulse (Isp) as it undergoes decomposition from combustion or decomposition by other means such as by catalytic decomposition. A monopropellant generally has a high freezing point and a low Isp. These properties therefore exclude the use of monopropellants in certain tactical situations.
An extensively used monopropellant such as hydrazine has been used as a rocket fuel. Hydrazine has a melting point of 2.degree. C. Hydrazine dissolves many inorganic substances and forms salts with inorganic acids. Hydrazine is miscible with water, methyl, ethyl, propyl, and isobutyl alcohols. Hydrazine forms an azeotropic mixture with water with a boiling point at 760 mm of mercury of 120.3.degree. C.
Although adding water to hydrazine would lower the freezing point of the mixture, the addition of a nonenergetic material would defeat the purpose of achieving a high specific impulse while lowering the freezing point.
Therefore, an object of this invention is to provide a series of additives to a monopropellant to lower the freezing point while enhancing the specific impulse.
A further object of this invention is to provide a series of additives to a monopropellant which are soluble in the monopropellant in sufficient amount to contribute to the specific impulse while lowering the freezing point of the monopropellant thereby enabling the monopropellant with these additives to be used in tactical systems deployed for use in cold environmental conditions.